Hello and Greetings.

I have had a rough time trying to figure out what to do - searched for a few days for an answer to no avail.

So I purchased a 1st Generation Mac Pro NVIDIA GeForce 8800 GT upgrade card for my 1st Generation Mac Pro.

Did a fresh install of 10.5, downloaded the OS X 10.5.2 combo updater and Leopard Graphics Updater 1.0. First installed the combo updater, then the LGU 1.0 and then put the new card in. Mac OS X boots to a blank ACD (20" connected via ADC to DVI Adapter) - the monitor wont even power on. BUT, it does boot Windows XP fine and the card runs great!!!

I have had several conversations with Applecare agents, whom I am convinced are not very knowledgeable... was referred to "product specialists" that do the same thing I do - Google searches while your on the phone with them.

Anyway, they sent me a data capture program and I sent the data back, but haven't heard from them yet.

A few things - 1st, I ran fresh installs twice - first time downloading both the 10.5.2 combo and the LGU 1.0... as stated - it didn't work. Then upgraded to 10.5.6 with the combo updater (as per recommendation of aplcare) - it also did not work. I did another fresh install of 10.5, dl'ed the combo updater for 10.5.2 - this time I was going to run Software Update for my LGU 1.0 and it didn't show up! ???? So I dl'ed IT again - this is where I am now.

Other steps I took...
Pulled all third party items out of the MP (ram, cards, hdds etc)
reset nvram / pram
reset SMC

If I look in /System/Library/Extensions - it seems all of my nvidia related files (including 8XXXGTDriver) are still from 2007 - LGU doesn't seem to be installing anything, though the logs say the package installed fine.

Perhaps a corrupted firmware of sorts? I haven't flashed anything and this is a card I bought from apple for the correct generation. Why would t work in XP and not OSX?

Any help is greatly appreciated.